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cc65/libsrc/common/longjmp.s
2015-09-11 14:18:22 -04:00

53 lines
1.1 KiB
ArmAsm

;
; 1998-06-06, Ullrich von Bassewitz
; 2015-09-11, Greg King
;
; void __fastcall__ longjmp (jmp_buf buf, int retval);
;
.export _longjmp
.import popax
.importzp sp, ptr1, ptr2
_longjmp:
sta ptr2 ; Save retval
stx ptr2+1
ora ptr2+1 ; Check for 0
bne @L1
inc ptr2 ; 0 is illegal, according to the standard ...
; ... and, must be replaced by 1
@L1: jsr popax ; get buf
sta ptr1
stx ptr1+1
ldy #0
; Get the old parameter stack
lda (ptr1),y
iny
sta sp
lda (ptr1),y
iny
sta sp+1
; Get the old stack pointer
lda (ptr1),y
iny
tax
txs
; Get the return address and push it on the stack
lda (ptr1),y
iny
pha
lda (ptr1),y
pha
; Load the return value and return to the caller
lda ptr2
ldx ptr2+1
rts